There is a lot of positivity in this post and I like it but I can't agree with all you wrote.
The most of us can't always choose to stay positive or to turn negative, there are things we can't control, there are things that make us unable to control ourselves. Very much depends on your life experience, your present situation and on people around you. You live in a city that is much bigger than mine, you can actually choose not to see the same people every day. That's impossible here.
We all can produce positive and negative energy in ourselves. And we receive positive and negative energy from our environment. I produce only positive energy in myself because 80% of the energy that I receive from outside is negative. So I have to produce only the positive energy just to make a balance.
I have a key to stay positive: I don't take 80% things that happen around seriously. Too much "serious" causes you stress. Being #whysoserious makes me relaxed. It compensates my lack of sleep.